The rapid transmission of COVID-19 has intensified the need for understanding how diseases spread. Virus-laden aerosols flow into the human respiratory system and deposit in airways, resulting in severe acute respiratory syndrome, a leading cause of death for COVID victims. Since some regions in the respiratory system are more susceptible to viral aerosols, investigating aerosol dynamics inside the human body, rather than the outside environment, becomes especially important.

To better understand aerosol transmission, Shim et al. conducted numerical simulations using an anatomically accurate model. While most existing literature simulates aerosol dynamics using simplified geometrical models, the team’s detailed approach allowed them to vary realistic settings such as breathing rates, breathing modes, and viral aerosol sizes to encompass everyday scenarios.

“Through simulations, we gain invaluable insights into the behavior of viral aerosols, helping us understand their movement and potential impacts on the human bodies,” said author Suo Yang. “This knowledge is essential for studying the transmission of airborne diseases and for devising effective strategies to mitigate their spread.”

The authors identified regions of the respiratory system most susceptible to viral aerosol deposition and the breathing speed that enables higher deposition. They also found the characteristic particle size and flow speed that best facilitates targeted aerosol drug delivery. Both findings could have widespread applications in medical research and technology development.

“We anticipate more medical researchers to use computational fluid dynamics (CFD) tools to investigate virus transmission,” said Yang. “And that more CFD researchers will leverage anatomically accurate models from the CT scans of real human respiratory systems for such studies, which will push the boundaries of biological fluid dynamics simulations.”

Source: “Numerical simulation of virus-laden aerosol transmission in real human respiratory airways,” by Gihun Shim, Sai Ranjeet Narayanan, and Suo Yang, Physics of Fluids (2023). The article can be accessed at

This paper is part of the Flow and the Virus Collection, learn more here.